A multitude of rigid articles molded of nylon are utilized by industry. It is well known that the impact strength of nylon articles is markedly increased when treated with water to increase the moisture content thereof. (See for example Engineering Properties of Thermoplastics, by R. M. Ogorkiewicz, Wiley-Interscience, New York, 1970). The moisture content of nylon parts has, in the past, been increased by (1) boiling the parts in water, (2) conditioning the parts at a required humidity, and (3) immersing the parts in cold water. Nylon appliance support feet, for example, have been conditioned for increased impact strength by soaking a large quantity of the parts in vats of cold water for a full twenty-four hour period. This process is time consuming and requires a great deal of space for the vats, and is thus costly. Further, as soon as the parts leave the water bath, the moisture content of the nylon begins to decrease and thus the impact strength thereof begins and continues to diminish.
According to the principles of the present invention, rigid nylon articles are provided with an internal chamber into which is sealed a quantity of water. The water, being in intimate contact with the nylon, continues to be absorbed by the nylon from within to replenish the moisture lost from the article to the surrounding atmosphere. In this manner the moisture content of the nylon is maintained at a maximum level until the water supply within the nylon article is exhausted. Inasmuch as the moisture is lost from the nylon relatively slowly in most applications, the water supply will last for years, thus nylon parts produced according to the principles of the invention will maintain the maximum impact resistance thereof years longer than parts treated by conventional methods.
It is therefore an object of the invention to improve the impact resistance of rigid nylon articles by the process of providing the article with an internal water-encapsulating chamber so that water will continually be in intimate contact with the nylon to replenish the moisture content of the nylon as moisture is lost therefrom to the atmosphere.
It is a further object to produce rigid nylon articles, according to the process of the invention, which exhibit maximum impact resistance for a longer period of time as compared with nylon articles treated according to conventional methods.
It is a still further object of the invention to provide a process for water conditioning rigid nylon parts which is simple, inexpensive, and does not require a long production time to accomplish.